The present invention generally relates to DC--DC converters, and more particularly to a parallel control type DC--DC converter which supplies power to a load from a plurality of converters.
A DC--DC converter is used as a power source of electronic equipment, and is particularly used as a power source for portable for portable equipment which uses batteries. In such equipment, the batteries are connected in parallel so as to increase the power source capacity, or the batteries are connected in series, and the voltage is converted into a predetermined voltage. If the batteries are directly connected in parallel, a circulating current flows among the batteries due to the differences in the voltages and internal resistances among the batteries. For this reason, the batteries are connected in parallel via diodes which prevent reverse-current flow. In this case, the forward voltage drop of the diode is large compared to the battery voltage, and there is a problem in that the use of the diode deteriorates the utilization efficiency of the batteries.